1. Field of the Invention
The present invention relates to phenol aralkyl resins, preparation processes thereof and epoxy resin compositions containing allylated phenol aralkyl resins. Particularly it relates to allyletherificated phenol aralkyl resins, allylated phenol aralkyl resins, preparation processes thereof and epoxy resin compositions containing allylated phenol aralkyl resins.
2. Prior Art
Allyletherificated phenol resins and allylated phenol resins obtained through the reaction of a phenol with an allyl halide are known. They are generally used as curing agents for epoxy and maleimide resins. JP-A-04-023824/1992 (Tokkaihei) discloses a resin composition containing a polyallylphenol as a curing agent for epoxy resins.
Cured products containing the known allylated phenol resins are excellent in intensity and rigidity at normal and high temperatures and their price is relatively inexpensive and stable in the market. However, they are apt to absorb relatively large amounts of moisture and are inferior in mechanical properties under high humidity conditions.
JP-A-04-004212/1992 (Tokkaihei) discloses an allylated product of phenol-aromatic hydrocarbon resin. The product is a constituent of a resin composition for sealing semiconductors and the resin composition is improved in moisture absorbability and low stress properties. However, it discloses neither an allyletherificated phenol aralkyl resin, nor an allylated phenol aralkyl resin, nor preparation processes thereof. A mixed solvent consisting of water and acetone is used in the examples, and the resulting resins are copolymers in which allyletherification and allylation of phenol nucleus proceed at the same time. Optionally, an allyletherificated phenol aralkyl resin is not obtained under the condition, nor is an allylated phenol aralkyl resin.
The above-mentioned copolymers are allylated phenol-aromatic hydrocarbon resin composition represented by the following formula, ##STR1## wherein R.sub.3 and R.sub.4 are hydrogen atoms or a methyl group, EQU 0&lt;a, b, c, d&lt;100 and a+b+c+d=100
a, b, c and d in the formula each stand for the percentage of the resin constituents.
With the marked advancement of technology in electric and electronic fields, there has been a demand for a resin which can ensure excellent qualities even when it is used in a small amount. For example, in the field of IC sealing materials, there is a demand for a resin which has excellent molding and processing properties, and a low viscosity so that it can be used as a filler with high filling capability. It is important to reduce viscosity while retaining the required heat and moisture resistant properties.